1. Field of the Invention
The present invention relates to mobile communication technology, and more particularly, to technology of transmitting uplink signals including ACK/NACK signals, control signals other than the ACK/NACK signals, and data signals.
2. Discussion of the Related Art
A user equipment (UE) of a mobile communication system transmits various signals through an uplink. Uplink signals transmitted by the user equipment can be segmented into data signals and control signals. Also, examples of the control signals transmitted to the uplink include uplink ACK/NACK signals for HARQ communication, channel quality indicator (CQI) information, and preceding matrix index (PMI).
3GPP LTE system uses a single carrier frequency division multiplexing access (SC-FDMA) scheme for uplink signal transmission. Also, the 3GPP LTE system prescribes that data signals and control signals among the uplink signals are first multiplexed and ACK/NACK signals are transmitted to the multiplexed signals by puncturing the data or control signals when uplink ACK/NACK signal transmission is required for downlink data. Hereinafter, in order that the ACK/NACK signals are divided from control signals other than the ACK/NACK signals, the control signals will mean those except for the ACK/NACK signals.
Meanwhile, Athens conference (#50) for 3GPP LTE has decided that data information is rate matched together with control information when the control information is multiplexed with the data information, wherein the control information is transmitted near a reference signal. This is to improve channel estimation performance by approximating all the control signals to the reference signal as the control signals generally require higher reliability than the data signals.
However, the control signals transmitted to the uplink include various signals as described above, and the ACK/NACK signals require higher reliability than the other control signals. In this case, when uplink ACK/NACK signal transmission is required while all the control signals are transmitted by approximating to the reference signal, problems occur in that the ACK/NACK signals can neither be transmitted by puncturing the control signals arranged near the reference signal nor be transmitted near the reference signal.
In this respect, a technology of transmitting uplink signals by efficiently arranging ACK/NACK signals and other control signals in a resource region considering priority among them is required.